Abstract: A stator for electrodynamic machines provides for more efficient design by reducing the total number of stator legs required for two-speed, two-phase motors and for generators producing electrical power at either of two frequencies while operating at a constant speed. This is accomplished by external switching, so that at one condition, all coils on all stator legs are energized in the normal symmetrical pattern, while at the other condition, all coils on all stator legs are energized in a non-symmetrical pattern.

Abstract: An electromagnetic machine of the type having a moving member and a stationary member, with a set of structures on the moving member to magnetically interact with a set of structures on the stationary member, has an improved construction comprising displacing by an angle of displacement, .alpha..sub.m, from their normal positions, a first portion of one set of structures whereby the displacement causes a harmonic of the fundamental torque/angle curve to be attenuated. The angle of displacement is determined by the following relationship:.alpha..sub.m =.alpha..sub.e /p,where.alpha..sub.e =displacement in electrical degrees,p=number of moving member magnetic pole pairs,further where .alpha..sub.e =180/h,where h=an integer equal to the number of a harmonic of the fundamental torque/angle curve to be attenuated.

Abstract: A stator for a stepping motor, the stator having a plurality of salient poles and at least two windings, each winding comprising at least two conductors each of which is wound upon one or more separate poles. The conductors of each winding may be connected either in series or in parallel. This winding arrangement is particularly advantageous when the conductors of each winding are connected in series and driven with a bipolar drive, as problems which exist with bifilar windings, such as high conductor-to-conductor potentials and inductive spikes, are avoided.

Abstract: An electromagnetic device of the type having a rotor and a stator with magnetically coacting peripheries, with the stator having toothed pole structures, has the stator pole teeth set at nonuniform spacing to improve the operating characteristics of the device. When the device is a stepping motor, improved step accuracy is attained through reduction of residual (or detent) torque. Reduction of airborne noise is reduced in all motor types.

Abstract: The rotor in each of the disclosed stepping motors comprises a permanent magnet disc between toothed pole pieces, the diameter of the magnet disc is essentially equal to the outer diameter of the toothed pole pieces.